This application claims benefit of Japanese Patent Application No. 2002-131617 filed on May 7, 2002, the contents of which are incorporated by the reference.
The present invention relates to portable telephone sets and, more particularly, to portable telephone sets for improving the user's operability and convenience.
Heretofore, to meet the demand for size reduction of the portable telephone set, a foldable type, the body of which is constituted by two units foldably coupled together by a coupling member, and a slide type, are used as well as a straight type which is constituted by a single body. The slide type portable telephone set usually comprises a main casing (i.e., first unit) and a movable casing (i.e., second unit) with some function parts mounted thereon, the two casings being slidably coupled together such that the movable casing is slidable in the long axis directions relative to the main casing. At the time of voice communication or the like, the portable telephone set can be used by slidably extending the two units away from each other in the long axis directions.
The above prior art portable telephone set has the following problem. The portable telephone set adopting the above slide type structure, which is usually constituted by the main casing and the movable casing with some function parts mounted thereon and coupled to the main casing such as to be slidable relative to the same in the long axis directions, is carried in a retreated state with the two units overlapped over each other. At the voice communication time, the portable telephone set is used with the two units slidably extended away from each other in the long axis directions by operating a lock release operator (i.e., one-touch slide button).
With the portable telephone set of the above structure, however, the position of the lock release operator (i.e., one-touch slide button) can not be recognized in a dark environment. Therefore, in such circumstance the button position can not be instantly specified, and subsequent smooth operation can not be smoothly obtained.